Segmented golden ratio radial reordering with variable temporal resolution for dynamic cardiac MRI
Fei Han1,2, Ziwu Zhou1,2, Stanislas Rapacchi1
1Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California, USA.
Magnetic Resonance in Medicine
|August 6, 2015
Summary
Golden ratio (GR) radial reordering in cardiac MRI can cause artifacts. A new segmented GR method improves k-space uniformity and image quality for ECG-gated imaging.
Area of Science:
- Medical Imaging
- Biophysics
Background:
- Golden Ratio (GR) radial reordering offers flexible temporal resolution in MRI by ensuring near-uniform k-space sampling.
- However, its application in electrocardiogram (ECG)-gated cardiac imaging is challenged by temporal partitioning of the reconstruction window, leading to non-uniform k-space coverage.
Purpose of the Study:
- To investigate image artifacts arising from conventional GR in ECG-gated cardiac imaging.
- To propose and evaluate a segmented GR method to mitigate these artifacts and improve k-space uniformity.
Main Methods:
- Computer simulations and phantom experiments assessed image artifacts from uniform radial, conventional GR, and segmented GR sampling.
- Two- and three-dimensional cardiac cine images were acquired in seven healthy subjects.
- Artifacts related to k-space sampling non-uniformity were graded by an experienced cardiac imager.
Main Results:
- Segmented GR demonstrated more uniform k-space sampling, independent of heart rate variations, compared to conventional GR.
- Cardiac cine images reconstructed with segmented GR exhibited significantly higher and more reliable image quality.
Conclusions:
- Segmented GR effectively resolves k-space non-uniformity issues when combining GR with ECG gating.
- This technique holds potential for various ECG-gated cardiac MRI applications, enabling retrospective selection of reconstruction windows.
